Inductive position sensor
Cross-reference to related applications
The sequence number that the application requires on September 21st, 2007 to submit to is that 60/974,206 U.S. Provisional Patent Application and the sequence number submitted on September 16th, 2008 are the right of priority of 12/211,360 U.S. Patent application, and these are applied for by being incorporated herein by reference.
Technical field
Relate generally to position transducer of the present invention, and relate more specifically to inductive position sensor.
Background technology
In motor vehicles, gas pedal (throttle pedal) is mechanically connected to engine throttle by cable traditionally.Yet in more modern vehicle, throttle position switch is mechanically connected on the pedal and produces the electrical output signal that the expression gas pedal is stepped on degree.This type systematic usually is called as " Flight By Wire (fly-by-wire) " system.
In one type throttle position switch, emitter coil or exciter coil are encouraged by high frequency source so that this emitter coil produces electromagnetic radiation.In addition, this emitter coil is configured to circular-mode, although also can use interchangeable other patterns.
Receiver coil also is set in the position transducer, and it is very near emitter coil.Therefore, in case to the emitter coil energising, because the coupling of the induction between emitter coil and the receiver coil, receiver coil produces output signal.
Yet different with emitter coil, receiver coil comprises first ring and second ring, and second ring oppositely twines with respect to first ring.Therefore, the induction coupling between first of emitter coil and the receiver coil ring produces the opposite voltage of responding to emitter coil of polarity of voltage in second ring of receiver coil.Therefore, the receiver output signal is from first ring of receiver coil and the combination or the summation of second voltage signal that encircles.
In order to produce the output signal of expression throttle position, coupler component be rotatably installed on the position transducer and with the stepping on and discharge synchronous rotation of gas pedal.In addition, this coupler component is made of the material of the electromagnetic radiation of conduction emitter coil emission.This coupler component covers the part of emitter coil and receiver coil.Therefore, in case coupler component moves or rotates, first ring of transmitter and receiver coil and the induction coupling between second ring are changed.This produces the output signal from receiver coil conversely, and this output signal changes along with the position, angle of coupler component, and therefore changes along with the position, angle of the gas pedal that is mechanically connected to coupler component.
If coupler component is accurately concentric with emitter coil and receiver coil, if and during whole the moving of coupler component, it is constant that spacing between coupler component and emitter coil and the receiver coil keeps, and the accurate indication and the therefore accurate position, angle of indicating gas pedal of the position, angle of coupler component then is provided from the output of receiver coil.Yet, in fact, during the manufacturing of accelerator pedal position sensor, manufacturing tolerance usually make in the throttle position switch coupler component not with emitter coil and receiver coil is accurately concentric and/or coupler component and emitter coil and receiver coil between the gap different with the gap of expectation a little.
Used different strategies to compensate the proper alignment that lacks between the axis of the pivot axis of coupler component and emitter coil and receiver coil.Yet the gap that these strategies are not enough to compensate between coupler component and emitter coil and the receiver coil changes, so that satisfy the accuracy requirement of accelerator pedal sensor.
Summary of the invention
The invention provides a kind of throttle position switch, it has overcome the above-mentioned shortcoming of present known throttle position switch.
In brief, throttle position switch of the present invention comprises the emitter coil that twines with circular configuration.Emitter coil is by the high-frequency alternating current source forcing, so that during energising, emitter coil produces electromagnetic radiation.
Receiver coil also is provided in the throttle position switch, and it is very near emitter coil.Receiver coil comprises first ring and second ring that oppositely twines, and first ring and second ring are electrically connected in series mutually.Yet because first ring of receiver coil and second ring oppositely twine mutually, the voltage of induction will be opposite with the polarity of voltage that emitter coil is responded in the second receiver ring in first ring when emitter coil is energized.Voltage summation in the receiver ring forms the output signal from throttle position switch.
Coupler component is movably mounted with respect to emitter coil and receiver coil.This coupler component passes the induction coupling of first ring and second ring of emitter coil and receiver coil along with the angle position change of coupler component.Conversely, the position, angle of coupler component changes along with the position of gas pedal.For example, coupler component moves the induction coupling between first ring that can increase emitter coil and receiver coil and reduces induction coupling between second ring of emitter coil and receiver coil simultaneously in the rotation of a direction, therefore change the output signal from receiver coil.The rotation of coupler component on opposite sense of rotation produces a contrary effect.
For the gap that compensates between coupler component and emitter coil and the receiver coil changes, emitter coil comprises outer ring portion and annular inner portion, and this annular inner portion is radially inwardly spaced apart with outer ring portion.Then, axially modulator or reference coil are wrapped between the interior part and outside branch of emitter coil, and receiver coil covers at least a portion of the outer shroud of emitter coil simultaneously.In fact, the interior ring that emitter coil is provided is by changing in the gap that provides extra induction compensating for coupling between emitter coil and the reference coil between coupler component and emitter coil and the receiver coil.
Description of drawings
Also will understand the present invention better in conjunction with the accompanying drawings with reference to following detailed description, similar in the accompanying drawings reference marker is indicated the similar parts in a plurality of views, wherein:
Fig. 1 is the planimetric map that comprises the printed circuit board (PCB) of emitter coil;
Fig. 2 is the planimetric map with printed circuit board (PCB) of emitter coil, receiver coil and reference coil;
Fig. 3 is the exploded view of the preferred embodiment of sensor of the present invention;
Fig. 4 is the side view of the preferred embodiment of the present invention; And
Fig. 5 is the planimetric map of exemplary coupler component.
Embodiment
At first with reference to figure 1, it shows the part of throttle position switch 10, for the clear part throttle position switch 10 that removed.Throttle position switch 10 comprises printed circuit board (PCB) 12, and this printed circuit board (PCB) 12 is generally comprised within the shell 15 (Fig. 4) with not contaminated and/or other damages of protection printed circuit board (PCB) 12.
Emitter coil 14 is formed on the printed circuit board (PCB) 12 in a usual manner.This emitter coil 14 comprises outer ring portion 16 and annular inner portion 18.The outer ring portion 16 of emitter coil and annular inner portion 18 with circular configuration around axis 22 twine and outer ring portion 16 and annular inner portion 18 in all windings of emitter coil 14 all be oriented identical sense of rotation.
Still with reference to figure 1, the end of emitter coil 14 is coupled to high-frequency ac power 24.In case AC power 24 is activated or switches on, the outer ring portion 16 and the annular inner portion 18 of emitter coil 14 produce electromagnetic radiation in the mode of knowing.
With reference now to Fig. 2 and Fig. 3,, have at least two rings 32 that oppositely twine and 34 receiver coil 30 and also utilize conventional printed circuit board (PCB) manufacturing technology to be formed on the printed circuit board (PCB) 12, so that receiver coil is set at the position of the outer ring portion 16 of very close emitter coil 14.In addition, Fig. 2 and Fig. 3 illustrate receiver coil and comprise five and twine clockwise 32 and five of sections and twine section 34 counterclockwise, so that section 32 and 34 equates on angle square cun and the axis 22 on printed circuit board (PCB) 12 replaces mutually.Yet Fig. 2 and Fig. 3 illustrate five electrode structures by way of example rather than are limited excessively.In addition, only essential is that receiver coil has at least two rings 32 and 34 that oppositely twine.
All rings 32 and 34 of receiver coil 30 are electrically connected in series mutually.Therefore, the voltage in the output 38 of receiver coil equals the summation of all the receiver rings 32 and 34 the voltage of receiver coil 30.Receiver output 38 is connected to circuit 39, and this circuit is special IC (ASIC) normally, and its processing and linearization are from the output of receiver coil 30.
Still also utilize conventional printed circuit board (PCB) manufacturing technology to be formed on the printed circuit board (PCB) 12 referring to figs. 2 and 3 a, reference coil or an axle modulator coil 40.The outer shroud 43 that reference coil 40 has annular inner portion 41 and oppositely twines, wherein annular inner portion 41 the interior part 16 of emitter coil 14 and outside between the part 18, the outer shroud 43 that oppositely twines is positioned on the printed circuit board (PCB) 12 around the periphery of receiver coil 30.The ring 41 of receiver coil 40 and the 43 sensed emitter coils 14 that are coupled to, ring 41 or oppositely winding different mutually with 43.Therefore, in case stimulated emission device coil 14, emitter coil induces voltage in the ring 41 and 43 of reference coil 40.Yet the polarity of the voltage of induction has opposite polarity with second voltage that encircles induction in 43 of reference coil 40 in the coil 41 of reference coil 40.
The ring 41 of reference coil 40 and 43 is electrically connected in series mutually, so that comprise voltage on the ring 41 and 43 of reference coil 40 from the output 46 of reference coil 40 and or poor.Electricity output 46 from reference coil 40 also is connected to circuit 39.
With reference now to Fig. 4 and Fig. 5,, coupler component 50 is positioned in the shell 15, so that coupler component 50 covers printed circuit board (PCB) 12 but be spaced apart with gap x with printed circuit board (PCB) 12.In addition, this coupler component 50 is rotated by axle 52 and is installed on the shell, and this is 52 coaxial with the axis 22 (Fig. 1) of emitter coil 14.
Fig. 4 and Fig. 5 illustrate coupler component 50 and have five blade/teats (lobe) 54, and its size and dimension is corresponding with the ring 32 and 34 of receiver coil 30.Should be appreciated that also the coupler component 50 shown in Fig. 5 only is to be illustrated at five utmost point position transducers.This position transducer can comprise still less or the more utmost point and do not depart from thought of the present invention or scope.
Coupler component 50 is made of the material that can conduct the electromagnetic radiation that is produced when emitter coil 14 is switched on by source of high frequency current 24 (Fig. 1).Therefore, the induction coupling between the ring 32 and 34 of emitter coil below the blade 54 change coupling mechanisms 50 of coupler component 50, especially coupler component and receiver coil 30.
Therefore, will increase the induction coupling of first ring between 32 of emitter coil 14 and receiver coil 30 at rotary coupler element 50 on the sense of rotation, the induction that reduces simultaneously between second ring 34 of emitter coil 14 and receiver coil 30 is coupled.Rotary coupler element 50 will produce a contrary effect on opposite sense of rotation.
Any situation no matter, by the induction coupling between the reverse winding around 32 and 34 that changes receiver coil 30 along with the position of rotation of coupler component 50, output voltage in the receiver coil output 38 will change equally, thereby produce the signal of the position of rotation of indication coupler component 50, this signal is handled with linearization by circuit 39 or is otherwise handled output signal.Coupler component 50 further is mechanical coupling to the assembly of throttle, feasible position of indicating throttle from the output signal of sensor 10.
Though the induction between the ring 32 and 34 of emitter coil 14 and receiver coil 30 coupling is along with the position of rotation of coupler component 50 changes, the induction coupling between the ring 41 and 43 of emitter coil 14 and reference coil 40 is independently and not along with the position of rotation variation of coupler component 50.Yet the induction coupling between the reverse winding ring 41 and 43 of reference coil 40 is really along with the gap x between coupler component 50 and the reference coil 40 changes.
The interior part 18 that has been found that emitter coil 14 keeps ratiometer function (ratiometric function) R (x) constant substantially with the surplus induction coupling that reference coil 40 provides, although gap x has the little variation of appropriateness, wherein R (x) is defined as:
R(x)=RM(x)/AM(x)
Wherein RM equals the output from receiver coil 30, and AM equals from the voltage in the output of reference coil 40, and x equals the value in the gap between coupler component 50 and the printed circuit board (PCB) 12.
In fact, it is constant substantially that function R keeps, although all there are the variation of appropriateness in emitter coil 14 on coupler component 50 and the printed circuit board (PCB) 12 and the gap x between the receiver coil 30.This further can improve the overall accuracy of throttle position switch 10.
According to above, the invention provides simply and efficiently position transducer as can be seen, such as throttle position switch,, uses by this sensor but also can being used for other.Yet, described after the present invention, apparent to those skilled in the art to its many modifications, it does not depart from the thought of the present invention that the scope by the claim of enclosing limits.